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United States Patent [191 [11] Patent Number: 4,592,782 Davies [45] Date of Patent: Jun. 3, 1986
[54] COMPOSITION OF MA'I'I‘ER 4,294,712 10/1981 Ueno et al...... 252/12 INCORPORATING POLYETHER ETHER 4,367,189 1/ 1983 Davies ...... 264/137 KETONE 4,380,523 4/1983 Lind et a1. .. 264/257 4,408,007 10/1983 Kuhls et a1. 524/546 [75] Inventor: Glyndwr J. Davies, Uxbridge, 4,421,588 12/1983 Davies ...... 156/3082 England 4,429,078 1/ 1984 Cogswell et a1. 525/165 [73] Assignee: AE PLC, Warwickshire, England 4,465,799 8/1984 Platkiewicz et a1. 523/457 [21] Appl. No.: 588,386 FOREIGN PATENT DOCUMENTS 2108983 5/1983 United Kingdom. [22] Filed: Mar. 12, 1984 2123430 2/1984 United Kingdom ...... 524/440 [30] Foreign Application Priority Data Primary Examiner-John F. Terapane Mar. 14, 1983 [GB] United Kingdom ...... 8306989 Assistant Examiner~Anne Brookes [51] 1111.01.‘ ...... B22F 1/00 Attorney, Agent, or Firm-Price, Heneveld, Huizenga & [52] us. c1...... 75/253; 252/12; Cooper 75/252; 525/934; 525/185; 524/440 [57] ABSTRACT [58] Field of Search ...... 252/12; 524/440; 525/185, 934; 521/919; 75/252, 253 A plain bearing comprising a steel backing, a sintered bronze interlayer and a lining of a material consisting of [56] References Cited polyether ether ketone, polytetra?uoroethylene, graph U.S. PATENT DOCUMENTS ite and bronze.
4,000,982 1/1977 Ueda ...... 252/12 4,064,097 12/ 1977 Korshak et al...... 524/440 6 Claims, No Drawings 4,592,782 1 2 tape. However, it may also be possible to mix and com COMPOSITION OF MATTER INCORPORAII‘ING pound the constituents and to extrude the tape directly. POLYETHER ETHER KETONE The composition may be moulded for use as a bearing or may be applied as a lining to a backing for example of BACKGROUND OF THE INVENTION 5 metal, preferably steel or aluminium. The composition Polyether ether ketone is a compound which is may be applied to the backing as a powder or a tape and known to have properties which make it suitable for is preferably roll bonded. An interlayer for example of many applications. It is relatively chemically inert, has tin or aluminium bronze is preferably applied to the a very high fatigue strength and has a low coef?cient of backing prior to the application of the composition. The friction. 10 tin bronze may be sintered to the backing and the alu One application for which PEEK has been suggested minium bronze may be are sprayed to the backing. is as a plain bearing material. However, when running Lining thicknesses above the bronze in the range under conditions of high speed with thin oil ?lms, 0.5-0.1 mm can be made. The bearing surface can be PEEK has been observed to suffer extreme temperature made with indentations, to provide lubricant reservoirs, rises resulting in failure of the bearing, both alone and or plain. with various additives. In a particular method of producing a composition in SUMMARY OF THE INVENTION accordance with the invention the composition is pulled from an extruder by haul-off rolls. This tends to cause It is an object of the present invention to provide a ?bration of the extrudate, which increases as the draw composition of matter having a good chemical resis down ratio increases (the draw-down ratio is the ratio tance and a fatigue strength comparable to that of of the haul-off rate to the natural extrusion rate). When PEEK but having an improved compatibility and coef made in this way, the composition tends to comprise ?cient of friction. drawn ?bres of PEEK matted and fused together, hav According to the invention, a composition of matter ing a void content in the range 10 to 70%. The PTFE comprises a mixture of polyether ketone together with 25 tends largely to be present as particles adhering to the polytetra?uoroethylene (PTFE), graphite and bronze. surface of the PEEK ?bres. Preferably the polyether ketone is polyether ether ke If the feed rate of the ?ne component powders is kept tone (PEEK). . deliberately low, a large volume of small air pockets Preferably the bronze is a tin bronze, for example an may be entrained in the melt. The small particle size of 11% tin bronze. Preferably the PEEK represents from 60% to 90% of the PEEK and the de-wetting effect of the PTFE pow the composition by weight, for example 70% to 85% by der may assist in producing a ?nely porous melt at the weight and most preferably 80% by weight. Preferably, extrusion die lips. Thus, when this is drawn as it the weight ratios of the remaining compounds are 1:324: emerges, a multitude of separate ?ne ?bres may be for graphite:PTFE:bronze. Thus, in the most preferred formed, assisted by the de-wetting effect of the PTFE. composition there would be 2.5% graphite, 7.5% PTFE This effect may be enhanced by adding a volatile agent and 10% bronze by weight. which “boils” as the material leaves the die. Any suit When used as a bearing material, such a composition able inert material having a boiling point less than about may show a fatigue strength comparable to that of 350° C. may be used, e.g. water, benzyl benzoate, di PEEK alone (i.e. higher than other polymeric bearing 40 phenyl ether etc. materials) together with a lower coefficient of friction. When this porous material is used as a bearing mate The material also tends to show a lower wear rate under rial, the porosity can provide a reservoir for oil or water and with grease and oil lubrication. grease within the material, thus providing a continuous The melting temperature of the material may be in lubricant supply. At the same time, the material may excess of 330° C.; the maximum continuous working 45 still exhibit high mechanical strength and wear resis temperature recommended is 250° C. although tempera tance, even with high porosity, because of the very high tures up to 300° C. can be tolerated for short periods. strength of the drawn PEEK ?bres and the fact that With conventional oils and greases the working temper they are fused together in the matrix. ature of the system will be limited to below 200° C. by If it is desired to produce a non-porous tape then it is the thermal stability of the lubricant. Synthetic lubri necessary to eliminate the voids entrained in the melt. cants may therefore be required to exploit fully the high This may be carried out by applying a low pressure at temperature potential. some stage (e.g. compounding) prior to the ?nal extru The material appears to be compatible with all the sion to remove any volatile matter. The material so common lubricants and degreasing ?uids. Unlike bear produced is a dark non-porous tape which does not ings based on acetal resins, the material of the invention exhibit ?bration. is not degraded by acidity produced in hydrocarbon oils To produce a plain bearing, a lining of the material used above 80° C. nor by shock absorber oils or by according to the invention is preferably bonded to a polyglycol or diester lubricants. It is also suitable for steel backing by way of a sintered bronze interlayer. use in hot water or oil/water emulsions. The backing, to which the interlayer has been applied is The composition may be made by any convenient 60 passed between two cooled rollers together with a tape method for example powder mixing or compounding of the material according to the invention. The temper followed by extrusion. The extruded mixture can be ature of the backing melts the tape locally and this is subsequently pelleted and comminuted and/or extruded forced into the interstices of the sinter. The composite is prior to use. cooled immediately to form a strong bond between In a preferred method of producing a tape of the 65 backing and lining. material, the constituents are mixed and compounded The material in accordance with the invention can and then extruded as strands. These are dried and also provide linings of increased thickness e.g. up to 4 chopped into pellets which are in turn extruded as a mm. When this is to be applied as a lining to a corre 4,592,782 3 4 spondingly thick backing, again preferably by way of a kg load, a PV factor of 0.7 N/mmZXm/S (20,000 sintered bronze interlayer, there may be a tendency for psi >< ft.m_in) for 500 hrs or until wear exceeded 0.25 mm the lining to peel off if applied by a cold rolling method, or seizure occurred for the comparative materials. In since the backing may retain more heat than can be order to obtain measurable wear rates in a reasonable removed immediately after rolling so that the lining 5 time, the PV was doubled in the case of HX (for HV, may not freeze effectively at the interface while stresses PV= 1.4 N/mmZXm/s (40,000 psi>